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A sweet LED accessory and its LED controller chip


#1

We were playing with a sweet LED matrix accessory, scroll:bit by Pimoroni https://shop.pimoroni.com/products/scroll-bit

Now, we want to use this with the BrainPad but to do so we will need to know what chip is used on there. Looking at the code https://github.com/pimoroni/pxt-scrollbit there is not a single mention of what chip is being used! I guess I can just start with their code and modify it to work. But I am still curious about this chip!

So, peeking under a microscope at this tiny chip

It is TINY!!! Do you want to see it next to a pen? It is 4x4mm only!

How come this tiny chip withe few pins drive 144 LEDs?! Doing some searching I found out it is a part by ISSI http://www.issi.com/WW/pdf/IS31FL3731.pdf

This chip is impressive, so good job for ISSI for making it and Pimoroni for using it. The board layout is also nice.

Next time I will be coding this little 4x4mm chip!


#2

Er, Gus, we were doing this with the Fez Domino a decade ago.


#3

I have never seen this before. Did you really use it?


#4

Well we were doing the charlieplexing with only 6 pins. I lost the video of it operating.

EDIT: 6 pins on 27 leds


#5

I have done charlieplexing long ago but the chip’s size is what surprised me. But I love seeing the domino :nerd_face:


#6

Interesting stuff guys! Never used it before.
Found this video interesting becuase of the way the LED were stacked


#7

I still have the 1,000~ish blue leds that I was planning to use to make a led cube. Couldn’t figure out how to wire them in 3d though.